Organic electroluminescent materials and devices

ABSTRACT

A compound comprising a ligand L A  according to formula (I) 
                         
as well as, a first device and a formulation including the same are disclosed. In the structure of formula (I): ring A is a 5- or 6-membered heteroaryl ring; X 1  is C or N; R A  is mono-, bi-, tri-, tetradentate, or unsubstituted; R A , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , and R 17  are independently selected from the group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, any adjacent substituents of R A , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , and R 17  are optionally joined to form a fused ring; the dashed lines represent bonds to a metal M; and metal M has an atomic number greater than 40.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/872,871, filed Sep. 3, 2013, the entire content of which isincorporated herein by reference.

PARTIES TO A JOINT RESEARCH AGREEMENT

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University, University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to compounds for use as emitters anddevices, such as organic light emitting diodes, including the same.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule istris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the followingstructure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processable” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY OF THE INVENTION

According to one embodiment, a compound comprising a ligand L_(A)according to formula (I)

is provided. In the structure of formula (I):

ring A is a 5- or 6-membered heteroaryl ring;

X₁ is C or N;

R_(A) is mono-, bi-, tri-, tetradentate, or unsubstituted;

R_(A), R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ are independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof;

any adjacent substituents of R_(A), R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆,and R₁₇ are optionally joined to form a fused ring;

the dashed lines represent bonds to a metal M; and

metal M has an atomic number greater than 40.

According to another embodiment, a first device comprising a firstorganic light emitting device is also provided. The first organic lightemitting device can include an anode, a cathode, and an organic layer,disposed between the anode and the cathode. The organic layer caninclude a compound comprising a ligand L_(A) according to formula (I).The first device can be a consumer product, an organic light-emittingdevice, and/or a lighting panel.

In still another embodiment, a formulation that includes a ligand L_(A)according to formula (I) is also provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows Formula (I), Formula (II), and Formula (III) as disclosedherein.

FIG. 4 is a graph of photoluminescent intensity versus wavelength forcompound 1.

FIG. 5 is a graph of photoluminescent intensity versus wavelength forcompound 2.

FIG. 6 is an Oak Ridge Thermal Ellipsoid Plot (ORTEP) drawing ofcompound 1.

FIG. 7 is an ORTEP drawing of compound 2.

FIG. 8 is a initial variable temperature NMR plot for compound 1 at (a)22° C., (b) 0° C., (c) −20° C., (d) −36° C., (e) −51° C., (f) −58° C.,(g) −68° C., and (h) −70° C.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, a cathode 160, and a barrier layer 170.Cathode 160 is a compound cathode having a first conductive layer 162and a second conductive layer 164. Device 100 may be fabricated bydepositing the layers described, in order. The properties and functionsof these various layers, as well as example materials, are described inmore detail in U.S. Pat. No. 7,279,704 at cols. 6-10, which areincorporated by reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F₄-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. Pat. No. 7,431,968, which is incorporated by reference in itsentirety. Other suitable deposition methods include spin coating andother solution based processes. Solution based processes are preferablycarried out in nitrogen or an inert atmosphere. For the other layers,preferred methods include thermal evaporation. Preferred patterningmethods include deposition through a mask, cold welding such asdescribed in U.S. Pat. Nos. 6,294,398 and 6,468,819, which areincorporated by reference in their entireties, and patterning associatedwith some of the deposition methods such as ink-jet and OVJD. Othermethods may also be used. The materials to be deposited may be modifiedto make them compatible with a particular deposition method. Forexample, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processability than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the presentinvention may further optionally comprise a barrier layer. One purposeof the barrier layer is to protect the electrodes and organic layersfrom damaging exposure to harmful species in the environment includingmoisture, vapor and/or gases, etc. The barrier layer may be depositedover, under or next to a substrate, an electrode, or over any otherparts of a device including an edge. The barrier layer may comprise asingle layer, or multiple layers. The barrier layer may be formed byvarious known chemical vapor deposition techniques and may includecompositions having a single phase as well as compositions havingmultiple phases. Any suitable material or combination of materials maybe used for the barrier layer. The barrier layer may incorporate aninorganic or an organic compound or both. The preferred barrier layercomprises a mixture of a polymeric material and a non-polymeric materialas described in U.S. Pat. No. 7,968,146, PCT Pat. Application Nos.PCT/US2007/023098 and PCT/US2009/042829, which are herein incorporatedby reference in their entireties. To be considered a “mixture”, theaforesaid polymeric and non-polymeric materials comprising the barrierlayer should be deposited under the same reaction conditions and/or atthe same time. The weight ratio of polymeric to non-polymeric materialmay be in the range of 95:5 to 5:95. The polymeric material and thenon-polymeric material may be created from the same precursor material.In one example, the mixture of a polymeric material and a non-polymericmaterial consists essentially of polymeric silicon and inorganicsilicon.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, medical monitors, televisions,billboards, lights for interior or exterior illumination and/orsignaling, heads up displays, fully transparent displays, flexibledisplays, laser printers, telephones, cell phones, personal digitalassistants (PDAs), laptop computers, digital cameras, camcorders,viewfinders, micro-displays, 3-D displays, vehicles, a large area wall,theater or stadium screen, or a sign. Various control mechanisms may beused to control devices fabricated in accordance with the presentinvention, including passive matrix and active matrix. Many of thedevices are intended for use in a temperature range comfortable tohumans, such as 18 degrees C. to 30 degrees C., and more preferably atroom temperature (20-25 degrees C.), but could be used outside thistemperature range, for example, from −40 degree C. to +80 degree C.

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The term “halo” or “halogen” as used herein includes fluorine, chlorine,bromine, and iodine.

The term “alkyl” as used herein contemplates both straight and branchedchain alkyl radicals. Preferred alkyl groups are those containing fromone to fifteen carbon atoms and includes methyl, ethyl, propyl,isopropyl, butyl, isobutyl, tert-butyl, and the like. Additionally, thealkyl group may be optionally substituted.

The term “cycloalkyl” as used herein contemplates cyclic alkyl radicals.Preferred cycloalkyl groups are those containing 3 to 7 carbon atoms andincludes cyclopropyl, cyclopentyl, cyclohexyl, and the like.Additionally, the cycloalkyl group may be optionally substituted.

The term “alkenyl” as used herein contemplates both straight andbranched chain alkene radicals. Preferred alkenyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkenyl groupmay be optionally substituted.

The term “alkynyl” as used herein contemplates both straight andbranched chain alkyne radicals. Preferred alkynyl groups are thosecontaining two to fifteen carbon atoms. Additionally, the alkynyl groupmay be optionally substituted.

The terms “aralkyl” or “arylalkyl” as used herein are usedinterchangeably and contemplate an alkyl group that has as a substituentan aromatic group. Additionally, the aralkyl group may be optionallysubstituted.

The term “heterocyclic group” as used herein contemplates aromatic andnon-aromatic cyclic radicals. Hetero-aromatic cyclic radicals also meansheteroaryl. Preferred hetero-non-aromatic cyclic groups are thosecontaining 3 or 7 ring atoms which includes at least one hetero atom,and includes cyclic amines such as morpholino, piperidino, pyrrolidino,and the like, and cyclic ethers, such as tetrahydrofuran,tetrahydropyran, and the like. Additionally, the heterocyclic group maybe optionally substituted.

The term “aryl” or “aromatic group” as used herein contemplatessingle-ring groups and polycyclic ring systems. The polycyclic rings mayhave two or more rings in which two carbons are common to two adjoiningrings (the rings are “fused”) wherein at least one of the rings isaromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryl,heterocycles, and/or heteroaryls. Additionally, the aryl group may beoptionally substituted.

The term “heteroaryl” as used herein contemplates single-ringhetero-aromatic groups that may include from one to three heteroatoms,for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole,triazole, pyrazole, pyridine, pyrazine and pyrimidine, and the like. Theterm heteroaryl also includes polycyclic hetero-aromatic systems havingtwo or more rings in which two atoms are common to two adjoining rings(the rings are “fused”) wherein at least one of the rings is aheteroaryl, e.g., the other rings can be cycloalkyls, cycloalkenyls,aryl, heterocycles, and/or heteroaryls. Additionally, the heteroarylgroup may be optionally substituted.

The alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group,aryl, and heteroaryl may be optionally substituted with one or moresubstituents selected from the group consisting of hydrogen, deuterium,halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether,ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

As used herein, “substituted” indicates that a substituent other than His bonded to the relevant position, such as carbon. Thus, for example,where R¹ is mono-substituted, then one R¹ must be other than H.Similarly, where R¹ is di-substituted, then two of R¹ must be other thanH. Similarly, where R¹ is unsubstituted, R¹ is hydrogen for allavailable positions.

The “aza” designation in the fragments described herein, i.e.aza-dibenzofuran, aza-dibenzothiophene, etc. means that one or more ofthe C—H groups in the respective fragment can be replaced by a nitrogenatom, for example, and without any limitation, azatriphenyleneencompasses both dibenzo[f,h]quinoxaline and dibenzo[f,h]quinoline. Oneof ordinary skill in the art can readily envision other nitrogen analogsof the aza-derivatives described above, and all such analogs areintended to be encompassed by the terms as set forth herein.

It is to be understood that when a molecular fragment is described asbeing a substituent or otherwise attached to another moiety, its namemay be written as if it were a fragment (e.g. phenyl, phenylene,naphthyl, dibenzofuryl) or as if it were the whole molecule (e.g.benzene, naphthalene, dibenzofuran). As used herein, these differentways of designating a substituent or attached fragment are considered tobe equivalent.

A compound comprising a ligand L_(A) according to formula (I)

is described. In the structure of formula (I):

ring A is a 5- or 6-membered heteroaryl ring;

X₁ is C or N;

R_(A) is mono-, bi-, tri-, tetradentate, or unsubstituted;

R_(A), R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ are independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof;

any adjacent substituents of R_(A), R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆,and R₁₇ are optionally joined to form a fused ring;

the dashed lines represent bonds to a metal M; and

metal M has an atomic number greater than 40.

In some embodiments, the metal M is selected from the group consistingof Ir, Rh, Re, Ru, Os, Pt, Au, and Cu.

In some embodiments, the compound has the structureM(L_(A))_(x)(L_(B))_(y)(L)_(z), where:

ligand L_(B) is

ligand L_(C) is

x is 1, 2, or 3;

y is 0, 1, or 2;

z is 0, 1, or 2;

x+y+z is the oxidation state of the metal M;

R₇ and R₉ are independently selected from group consisting of hydrogen,alkyl, cycloalkyl, aryl, and heteroaryl;

R₈ is selected from group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof;

rings C and D are each independently a 5- or 6-membered carbocyclic orheterocyclic ring;

R_(C) and R_(D) each independently represent mono, di, tri, or tetrasubstitution, or no substitution;

each of R_(C) and R_(D) are independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; and

any adjacent substitutents of R_(C) and R_(D) are optionally joined toform a ring.

In some embodiments, at least one of R₇, R₈, and R₉ has at least two Catoms. In some embodiments, two or three of R₇, R₈, and R₉ have at leasttwo C atoms.

In some embodiments, at least one of R₇, R₈, and R₉ has at least three Catoms. In some embodiments, two or three of R₇, R₈, and R₉ have at leastthree C atoms.

In some embodiments, at least one of R₇, R₈, and R₉ has at least four Catoms. In some embodiments, two or three of R₇, R₈, and R₉ have at leastfour C atoms.

In some embodiments, y is 1 or 2.

In some embodiments, the compound is homoleptic. In other embodiments,the compound is heteroleptic.

In some embodiments, each R_(A) is independently selected from the groupconsisting of hydrogen, alkyl, aryl, and combinations thereof. In someembodiments, at least one R_(A) is selected from the group consisting ofmethyl, ethyl, propyl, 1-methylethyl, butyl, 1-methylpropyl,2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclobutyl,cyclopentyl, cyclohexyl, partially or fully deuterated variants thereof,and combinations thereof.

In some more specific embodiments, ligand L_(A) is selected from thegroup consisting of:

where:

R₁, R₂, R₃, R₄, R₅, and R₆ are independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; and

any adjacent substituents of R₁, R₂, R₃, R₄, R₅, and R₆ are optionallyjoined to form a fused ring.

In some embodiments, at least one of R₁, R₂, R₃, R₄, R₅, and R₆ isselected from the group consisting of ethyl, ethyl, propyl,1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl,1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl,1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclobutyl, cyclopentyl,cyclohexyl, partially or fully deuterated variants thereof, andcombinations thereof.

In some embodiments, the compound comprises a ligand L_(D) bonded to themetal M, wherein the ligand L_(D) is selected from the group consistingof:

where L_(D13) is bonded to metal M by two, three or four of the N atomsthat are ortho to boron to form a bidentate, tridentate, or tetradentateligand, and

where L_(D14) is bonded to metal M by the two N atoms ortho to boron toform a bidentate ligand.

In some embodiments, the compound includes one or two ligandsindependently selected from ligand L_(D).

In some embodiments, ligand L_(A) has a structure according to formula(II):

where:

X₂, X₃, and X₄ are each independently C or N;

R₁, R₂, and R₃ are independently selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof;

any adjacent substituents of R₁, R₂, and R₃ are optionally joined toform a fused ring; and

R_(A) is mono-, bi-, tridentate, or unsubstituted.

In some embodiments, at least one of X₁ to X₄ is N. In some embodiments,at least two of X₁ to X₄ are N. In some embodiments, three of X₁ to X₄are N. In some embodiments, three of X₁ to X₄ are C.

In some embodiments, ligand L_(A) has a structure according to formula(III):

where:

X₂, X₃, X₄, and X₅ are each independently C or N;

R₁, R₂, R₃, and R₄ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof; and

any adjacent substituents of R₁, R₂ R₃, and R₄ are optionally joined toform a fused ring.

In some embodiments, at least one of X₁ to X₅ is N. In some embodiments,at least two of X₁ to X₅ are N, while at least three of X₁ to X₅ are Nin other embodiments. In some embodiments, four of X₁ to X₅ are N.

According to another aspect of the present disclosure, a first device isalso provided. The first device includes a first organic light emittingdevice, that includes an anode, a cathode, and an organic layer disposedbetween the anode and the cathode. The organic layer may include a hostand a phosphorescent dopant. The organic layer can include a compoundincluding a ligand L_(A) according to formula (I), and its variations asdescribed herein.

The first device can be one or more of a consumer product, an organiclight-emitting device and a lighting panel. The organic layer can be anemissive layer and the compound can be an emissive dopant in someembodiments, while the compound can be a non-emissive dopant in otherembodiments.

The organic layer can also include a host. In some embodiments, the hostcan include a metal complex. The host can be a triphenylene containingbenzo-fused thiophene or benzo-fused furan. Any substituent in the hostcan be an unfused substituent independently selected from the groupconsisting of C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂,N(Ar₁)(Ar₂), CH═CH—C_(n)H_(2n+1), C≡C—C_(n)H_(2n+1), Ar₁, Ar₁—Ar₂, andC_(n)H_(2n)—Ar₁, or no substitution. In the preceding substituents n canrange from 1 to 10; and Ar₁ and Ar₂ can be independently selected fromthe group consisting of benzene, biphenyl, naphthalene, triphenylene,carbazole, and heteroaromatic analogs thereof.

The host can be a compound comprising at least one chemical groupselected from the group consisting of triphenylene, carbazole,dibenzothiphene, dibenzofuran, dibenzoselenophene, azatriphenylene,azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, andaza-dibenzoselenophene. The host can include a metal complex. The hostcan be a specific compound selected from the group consisting of:

and combinations thereof.

In yet another aspect of the present disclosure, a formulation thatcomprises a compound including a ligand L_(A) according to formula (I),and its variations as described herein. The formulation can include oneor more components selected from the group consisting of a solvent, ahost, a hole injection material, hole transport material, and anelectron transport layer material, disclosed herein.

Combination with other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but not limit to: aphthalocyanine or porphyrin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and silane derivatives; a metal oxide derivative, suchas MoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butnot limit to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting of aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, and azulene; the group consistingof aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Wherein each Ar isfurther substituted by a substituent selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof.

In one aspect, Ar¹ to Ar⁹ is independently selected from the groupconsisting of:

wherein k is an integer from 1 to 20; X¹⁰¹ to X¹⁰⁸ is C (including CH)or N; Z¹⁰¹ is NAr¹, O, or S; Ar¹ has the same group defined above.

Examples of metal complexes used in HIL or HTL include, but not limit tothe following general formula:

wherein Met is a metal, which can have an atomic weight greater than 40;(Y¹⁰¹-Y¹⁰²) is a bidentate ligand, Y¹⁰¹ and Y¹⁰² are independentlyselected from C, N, O, P, and S; L¹⁰¹ is an ancillary ligand; k′ is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and k′+k″ is the maximum number of ligands thatmay be attached to the metal.

In one aspect, (Y¹⁰¹-Y¹⁰²) is a 2-phenylpyridine derivative. In anotheraspect, (Y¹⁰¹-Y¹⁰²) is a carbene ligand. In another aspect, Met isselected from Ir, Pt, Os, and Zn. In a further aspect, the metal complexhas a smallest oxidation potential in solution vs. Fc⁺/Fc couple lessthan about 0.6 V.

Host:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant. While the Table below categorizes host materials as preferredfor devices that emit various colors, any host material may be used withany dopant so long as the triplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

wherein Met is a metal; (Y¹⁰³-Y¹⁰⁴) is a bidentate ligand, Y¹⁰³ and Y¹⁰⁴are independently selected from C, N, O, P, and S; L¹⁰¹ is an anotherligand; k′ is an integer value from 1 to the maximum number of ligandsthat may be attached to the metal; and k′+k″ is the maximum number ofligands that may be attached to the metal.

In one aspect, the metal complexes are:

wherein (O—N) is a bidentate ligand, having metal coordinated to atoms Oand N.

In another aspect, Met is selected from Ir and Pt. In a further aspect,(Y¹⁰³-Y¹⁰⁴) is a carbene ligand.

Examples of organic compounds used as host are selected from the groupconsisting of aromatic hydrocarbon cyclic compounds such as benzene,biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene,phenanthrene, fluorene, pyrene, chrysene, perylene, and azulene; thegroup consisting of aromatic heterocyclic compounds such asdibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene,benzofuran, benzothiophene, benzoselenophene, carbazole,indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole,triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole,thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine,oxazine, oxathiazine, oxadiazine, indole, benzimidazole, indazole,indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline,isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine,phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine,phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and the group consisting of 2 to 10 cyclic structural units which aregroups of the same type or different types selected from the aromatichydrocarbon cyclic group and the aromatic heterocyclic group and arebonded to each other directly or via at least one of oxygen atom,nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom,chain structural unit and the aliphatic cyclic group. Wherein each groupis further substituted by a substituent selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof.

In one aspect, the host compound contains at least one of the followinggroups in the molecule:

wherein R¹⁰¹ to R¹⁰⁷ is independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof, when it is aryl or heteroaryl, ithas the similar definition as Ar's mentioned above. k is an integer from0 to 20 or 1 to 20; k′″ is an integer from 0 to 20. X¹⁰¹ to X¹⁰⁸ isselected from C (including CH) or N. Z¹⁰¹ and Z¹⁰² is selected fromNR¹⁰¹, O, or S.HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies as compared to a similar device lacking a blocking layer.Also, a blocking layer may be used to confine emission to a desiredregion of an OLED.

In one aspect, compound used in HBL contains the same molecule or thesame functional groups used as host described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

wherein k is an integer from 1 to 20; L¹⁰¹ is an another ligand, k′ isan integer from 1 to 3.ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

wherein R¹⁰¹ is selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof, when it is aryl or heteroaryl, it has the similar definition asAr's mentioned above. Ar¹ to Ar³ has the similar definition as Ar'smentioned above. k is an integer from 1 to 20. X¹⁰¹ to X¹⁰⁸ is selectedfrom C (including CH) or N.

In another aspect, the metal complexes used in ETL contains, but notlimit to the following general formula:

wherein (O—N) or (N—N) is a bidentate ligand, having metal coordinatedto atoms O, N or N,N; L¹⁰¹ is another ligand; k′ is an integer valuefrom 1 to the maximum number of ligands that may be attached to themetal.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated. Thus, anyspecifically listed substituent, such as, without limitation, methyl,phenyl, pyridyl, etc. encompasses undeuterated, partially deuterated,and fully deuterated versions thereof. Similarly, classes ofsubstituents such as, without limitation, alkyl, aryl, cycloalkyl,heteroaryl, etc. also encompass undeuterated, partially deuterated, andfully deuterated versions thereof.

In addition to and/or in combination with the materials disclosedherein, many hole injection materials, hole transporting materials, hostmaterials, dopant materials, exiton/hole blocking layer materials,electron transporting and electron injecting materials may be used in anOLED. Non-limiting examples of the materials that may be used in an OLEDin combination with materials disclosed herein are listed in Table Abelow. Table A lists non-limiting classes of materials, non-limitingexamples of compounds for each class, and references that disclose thematerials.

TABLE A MATERIAL EXAMPLES OF MATERIAL PUBLICATIONS Hole injectionmaterials Phthalocyanine and porphryin compounds

Appl. Phys. Lett. 69, 2160 (1996) Starburst triarylamines

J. Lumin. 72-74, 985 (1997) CF_(x) Fluorohydrocarbon polymer

Appl. Phys. Lett. 78, 673 (2001) Conducting polymers (e.g., PEDOT:PSS,polyaniline, polypthiophene)

Synth. Met. 87, 171 (1997) WO2007002683 Phosphonic acid and sliane SAMS

US20030162053 Triarylamine or polythiophene polymers with conductivitydopants

EP1725079A1 and

Organic compounds with conductive inorganic compounds, such asmolybdenum and tungsten oxides

US20050123751 SID Symposium Digest, 37, 923 (2006) WO2009018009 n-typesemiconducting organic complexes

US20020158242 Metal organometallic complexes

US20060240279 Cross-linkable compounds

US20080220265 Polythiophene based polymers and copolymers

WO2011075644 EP2350216 Hole transporting materials Triarylamines (e.g.,TPD, α-NPD)

Appl. Phys. Lett. 51, 913 (1987)

U.S. Pat. No. 5,061,569

EP650955

J. Mater. Chem. 3, 319 (1993)

Appl. Phys. Lett. 90, 183503 (2007)

Appl. Phys. Lett. 90, 183503 (2007) Triaylamine on spirofluorene core

Synth. Met. 91, 209 (1997) Arylamine carbazole compounds

Adv. Mater. 6, 677 (1994), US20080124572 Triarylamine with(di)benzothiophene/ (di)benzofuran

US20070278938, US20080106190 US20110163302 Indolocarbazoles

Synth. Met, 111, 421 (2000) Isoindole compounds

Chem. Mater. 15, 3148 (2003) Metal carbene complexes

US20080018221 Phosphorescent OLED host materials Red hostsArylcarbazoles

Appl. Phys. Lett. 78, 1622 (2001) Metal 8-hydroxy- quinolates (e.g.,Alq₃, BAlq)

Nature 395, 151 (1998)

US20060202194

WO2005014551

WO2006072002 Metal phenoxy- benzothiazole compounds

Appl. Phys. Lett. 90, 123509 (2007) Conjugated oligomers and polymers(e.g., polyfluorene)

Org. Electron. 1, 15 (2000) Aromatic fused rings

WO2009066779, WO2009066778, WO2009063833, US20090045731, US20090045730,WO2009008311, US20090008605, US20090009065 Zinc complexes

WO2010056066 Chrysene based compounds

WO2011086863 Green hosts Arylcarbazoles

Appl. Phys, Lett. 78, 1622 (2001)

US20030175553

WO2001039234 Aryltriphenylene compounds

US20060280965

US20060280965

WO2009021126 Poly-fused heteroaryl compounds

US20090309488 US20090302743 US20100012931 Donor acceptor type molecules

WO2008056746

WO2010107244 Aza- carbazole/ DBT/DBF

JP2008074939

US20100187984 Polymers (e.g., PVK)

Appl. Phys. Lett. 77, 2280 (2000) Spirofluorene compounds

WO2004093207 Metal phenoxy- benzooxazole compounds

WO2005089025

WO2006132173

JP200511610 Spirofluorene- carbazole compounds

JP2007254297

JP2007254297 Indolocabazoles

WO2007063796

WO2007063754 5-member ring electron deficient heterocycles (e.g.,triazole, oxadiazole)

J. Appl. Phys. 90, 5048 (2001)

WO2004107822 Tetraphenylene complexes

US20050112407 Metal phenoxypyridine compounds

WO2005030900 Metal coordination complexes (e.g., Zn, Al withN{circumflex over ( )}N ligands)

US20040137268, US20040137267 Blue hosts Arylcarbazoles

Appl. Phys, Lett, 82, 2422 (2003)

US20070190359 Dibenzothiophene/ Dibenzofuran- carbazole compounds

WO2006114966, US20090167162

US20090167162

WO2009086028

US20090030202, US20090017330

US20100084966 Silicon aryl compounds

US20050238919

WO2009003898 Silicon/ Germanium aryl compounds

EP2034538A Aryl benzoyl ester

WO2006100298 Carbazole linked by non- conjugated groups

US20040115476 Aza-carbazoles

US20060121308 High triplet metal organometallic complex

U.S. Pat. No. 7,154,114 Phosphorescent dopants Red dopants Heavy metalporphyrins (e.g., PtOEP)

Nature 395, 151 (1998) Iridium(III) organometallic complexes

Appl. Phys. Lett. 78, 1622 (2001)

US20030072964

US20030072964

US20060202194

US20060202194

US20070087321

US20080261076 US20100090591

US20070087321

Adv. Mater. 19, 739 (2007)

WO2009100991

WO2008101842

U.S. Pat. No. 7,232,618 Platinum(II) organometallic complexes

WO2003040257

US20070103060 Osminum(III) complexes

Chem. Mater. 17, 3532 (2005) Ruthenium(II) complexes

Adv. Mater. 17, 1059 (2005) Rhenium (I), (II), and (III) complexes

US20050244673 Green dopants Iridium(III) organometallic complexes

Inorg. Chem. 40, 1704 (2001)

US20020034656

U.S. Pat. No. 7,332,232

US20090108737

WO2010028151

EP1841834B

US20060127696

US20090039776

U.S. Pat. No. 6,921,915

US20100244004

U.S. Pat. No. 6,687,266

Chem. Mater. 16, 2480 (2004)

US20070190359

US20060008670 JP2007123392

WO2010086089, WO2011044988

Adv. Mater. 16, 2003 (2004)

Angew. Chem. Int. Ed. 2006, 45, 7800

WO2009050290

US20090165846

US20080015355

US20010015432

US20100295032 Monomer for polymeric metal organometallic compounds

U.S. Pat. No. 7,250,226, U.S. Pat. No. 7,396,598 Pt(II) organometalliccomplexes, including polydentated ligands

Appl. Phys. Lett. 86, 153505 (2005)

Appl. Phys. Lett. 86, 153505 (2005)

Chem. Lett. 34, 592 (2005)

WO2002015645

US20060263635

US20060182992 US20070103060 Cu complexes

WO2009000673

US20070111026 Gold complexes

Chem. Commun. 2906 (2005) Rhenium(III) complexes

Inorg. Chem. 42, 1248 (2003) Osmium(II) complexes

U.S. Pat. No. 7,279,704 Deuterated organometallic complexes

US20030138657 Organometallic complexes with two or more metal centers

US20030152802

U.S. Pat. No. 7,090,928 Blue dopants Iridium(III) organometalliccomplexes

WO2002002714

WO2006009024

US20060251923 US20110057559 US20110204333

U.S. Pat. No. 7,393,599, WO2006056418, US20050260441, WO2005019373

U.S. Pat. No. 7,534,505

WO2011051404

U.S. Pat. No. 7,445,855

US20070190359, US20080297033 US20100148663

U.S. Pat. No. 7,338,722

US20020134984

Angew. Chem. Int. Ed. 47, 4542 (2008)

Chem. Mater. 18, 5119 (2006)

Inorg. Chem, 46, 4308 (2007)

WO2005123873

WO2005123873

WO2007004380

WO2006082742 Osmium(II) complexes

U.S. Pat. No. 7,279,704

Organometallics 23, 3745 (2004) Gold complexes

Appl, Phys, Lett. 74, 1361 (1999) Platinum(II) complexes

WO2006098120, WO2006103874 Pt tetradentate complexes with at least onemetal- carbene bond

U.S. Pat. No. 7,655,323 Exciton/hole blocking layer materialsBathocuprine compounds (e.g., BCP, BPhen)

Appl. Phys. Lett. 75, 4 (1999)

Appl. Phys. Lett. 79, 449 (2001) Metal 8-hydroxy- quinolates (e.g.,BAlq)

Appl. Phys. Lett. 81, 162 (2002) 5-member ring electron deficientheterocycles such as triazole, oxadiazole, imidazole, benzoimidazole

Appl. Phys. Lett. 81, 162 (2002) Triphenylene compounds

US20050025993 Fluorinated aromatic compounds

Appl. Phys. Lett. 79, 156 (2001) Phenothiazine- S-oxide

WO2008132085 Silylated five-membered nitrogen, oxygen, sulfur orphosphorus dibenzo- heterocycles

WO2010079051 Aza-carbazoles

US20060121308 Electron transporting materials Anthracene- benzoimidazolecompounds

WO2003060956

US20090179554 Aza triphenylene derivatives

US20090115316 Anthracene- benzothiazole compounds

Appl. Phys. Lett. 89, 063504 (2006) Metal 8-hydroxy- quinolates (e.g.,Alq₃, Zrq₄)

Appl. Phys. Lett. 51, 913 (1987) U.S. Pat. No. 7,230,107 Metal hydroxy-benzoquinolates

Chem. Lett. 5, 905 (1993) Bathocuprine compounds such as BCP, BPhen, etc

Appl. Phys. Lett. 91, 263503 (2007)

Appl. Phys. Lett. 79, 449 (2001) 5-member ring electron deficientheterocycles (e.g., triazole, oxadiazole, imidazole, benzoimidazole)

Appl, Phys, Lett. 74, 865 (1999)

Appl. Phys, Lett. 55, 1489 (1989)

Jpn. J. Apply. Phys. 32, L917 (1993) Silole compounds

Org. Electron. 4, 113 (2003) Arylborane compounds

J. Am. Chem. Soc. 120, 9714 (1998) Fluorinated aromatic compounds

J. Am. Chem. Soc. 122, 1832 (2000) Fullerene (e.g., C60)

US20090101870 Triazine complexes

US20040036077 Zn (N{circumflex over ( )}N) complexes

U.S. Pat. No. 6,528,187

EXPERIMENTAL Synthesis of Compound 1 Step 1: Synthesis of2-(dibenzo[ghi,mno]fluoranthen-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

2-(dibenzo[ghi,mno]fluoranthen-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolanewas synthesized following the procedure published by Wegner, H. A.,Scott, L. T., Meijere, A., J. Org. Chem. 2003. 68 883-887.

Step 2: Synthesis of 2-(dibenzo[ghi,mno]fluoranthen-1-yl)pyridine

A 3 neck flask was charged with2-(dibenzo[ghi,mno]fluoranthen-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(500 mg, 1.33 mmol), 2-bromopyridine (0.14 mL, 1.46 mmol), cesiumcarbonate (2.17 g, 6.66 mmol), and dissolved in 50 mL toluene and 6 mLwater. A condenser was attached and the mixture was degassed for 40minutes, then tetrakis(triphenylphosphine)palladium(0) (154 mg, 0.133mmol) was added to the flask and the reaction mixture was heated toreflux for 18 hours. The mixture was then cooled to ambient temperatureand concentrated in vacuo. Column chromatography on silica gel wasperformed on the resultant crude mixture using 85%:15% Hexanes:EthylAcetate, which yielded 2-(dibenzo[ghi,mno]fluoranthen-1-yl)pyridine as apale yellow solid (250 mg, 57% yield). The molecular weight wasdetermined to be 327.35 g/mol by Matrix-assisted laserdesorption/ionization. NMR results confirmed the presence of2-(dibenzo[ghi,mno]fluoranthen-1-yl)pyridine: ¹H NMR (400 MHz,chloroform-d₁, δ) 7.37 (m, 1H), 7.82 (m, 5H), 7.85 (d, 1H), 7.87 (d, 1H)7.90 (m, 1H), 7.96 (m, 1H), 8.07 (d, 1H), 8.28 (s, 1H), 8.86 (m, 1H).

Step 3: Synthesis of Compound 1: [(corpy)Ir(ppz)₂]

A 3-neck flask was charged with2-(dibenzo[ghi,mno]fluoranthen-1-yl)pyridine (65 mg, 0.20 mmol),[(ppz)₂Ir(μ-Cl)₂Ir(ppz₂)] (100 mg, 0.1 mmol), potassium carbonate (116mg, 0.84 mmol), and 12 mL of 2-ethoxyethanol. A condenser was attachedto the flask and the reaction was degassed, then heated to 100° C. for24 hrs. The reaction mixture was then cooled to ambient temperature and10 mL of deionized water was added to dissolve excess potassiumcarbonate. An orange-red solid was vacuum filtered and washed with 10 mLof methanol and 10 mL hexanes, then air dried. Column chromatography onsilica gel was performed on the resultant crude mixture (100% methylenechloride) to yield compound 1 as an orange-red emissive solid (36 mg,75%). The molecular weight was determined to be 804.7 g/mol byMatrix-assisted laser desorption/ionization. NMR results confirmed thepresence of compound 1: ¹H NMR (400 MHz, acetone-d₆, δ) 6.30 (dd, 1H),6.43 (dd, 1H), 6.52 (dd, 1H), 6.57 (m, 2H), 6.68 (m, 1H), 6.80 (m, 1H),6.87 (m, 1H), 6.94 (m, 1H), 6.99 (m, 1H), 7.13 (ddd, 1H), 7.32 (d, 1H),7.51 (dd, 1H), 7.56 (m, 2H), 7.78 (d, 1H), 7.84 (d, 1H), 7.89 (m, 3H),8.03 (m, 1H), 8.26 (m, 1H), 8.43 (m, 2H), 8.49 (dd, 1H), 8.99 (d, 1H).

Synthesis of Compound 2 Synthesis of Compound 2: [(corpy)Pt(dDm)]

A 3 neck flask was charged with2-(dibenzo[ghi,mno]fluoranthen-1-yl)pyridine (142 mg, 0.43 mmol),potassium tetrachloroplatinate(II) (75 mg, 0.18 mmol) and 18 mL of a 3:1mixture of 2-ethoxyethanol:water. A condenser was attached to the flaskand the mixture was degassed and heated to 100° C. for 16 hrs. Thereaction was cooled to ambient temperature, water was added to themixture and filtered and an orange-yellow precipitate was isolated. Thissolid was then added to a new 3 neck flask, and then charged potassiumcarbonate (124 mg, 0.89 mmol) and charged with 2-ethoxyethanol. Acondenser was attached and the mixture was degassed after which2,2,5,5-tetramethylhexane-3,4-dione (56 μL, 0.27 mmol) was added and thereaction was heated to 75° C. for 16 hr. The reaction was then cooled toambient temperature and filtered and the precipitate was then washedwith methanol to give an orange-brown emissive solid (52 mg, 41%). MWwas found to be 704.8 g/mol by Matrix-assisted laserdesorption/ionization. ¹H NMR (400 MHz, chloroform-d₁, δ) 1.33 (s, 7H),1.43 (s, 7H) 5.99 (s, 1H) 7.14 (m, 1H), 7.79 (m, 5H), 7.92 (m, 1H), 8.20(d, 1H), 8.51 (d, 1H), 8.92 (d, 1H), 9.25 (dd, 1H).

Analysis of Photophysical Properties

As shown above, phosphorescent complexes that contain a singlemetal-carbon sigma bond where corannulene is cyclometalated to a metalcenter have been synthesized using techniques that provide the abilityto synthesize a diverse set of corannulene ligands bonded to a metalcenter. These complexes have photophysical properties that are affectedby bowl inversion of corannulene. By measuring the rate of bowlinversion, one can determine what amount of non-radiative decay is dueto inversion, which has never been directly measured in metal complexes.

Examples of some corannulene complexes and comparative complexes areshown below:

These corannulene based ligands produce a smaller red shift than wouldbe expected for the complexes. The conjugated π-system is greatlyincreased in the corannulene containing ligand compared to phenylpyridine (ppy) and napthyl pyridine (npy) complexes.

TABLE 1 Photophysical Data of Example Compounds λ_(max) Compound (nm) τQY Compound 1: [(ppz)₂Ir(corpy)] in solution 678 1.64 μs (64%) 0.0229.42 μs (36%) [(ppz)₂Ir(corpy)] at 77K 578 8.61 μs (87%) — 16.7 μs (13%)[Ir(ppy)₃] in solution 508 [(npy)₂Ir(acac)] in solution 600[(ppz)₂Ir(corpy)] in Poly(methyl 632 3.32 μs (14%) 0.202 methacrylate)(PMMA) 8.17 μs (86%) Compound 2: [(corpy)Pt(dpm)] in solution 660 5.05μs 0.053 [(corpy)Pt(dpm] at 77k 598 14.1 μs — [(corpy)Pt(dpm)] in PMMA654 12.2 μs 0.198 [(ppy)Pt(acac)] in solution 486 [(npy)Pt(dpm)] insolution 560

As shown in Table 1, the emission of corannulene pyridine complexes(corpy) is red shifted 50-100 nanometers from npy complexes. The modestsize of this red shift relative to npy complexes is surprising, becausethe π-system of the corpy ligand is more than double the size of the npyligand. The npy complexes have a single ring added, relative to ppy, andthey give the same red shift of approximately 100 nm. The additionalπ-conjugation on corpy red shift the emission to nearly the same extentthat a single fused ring did, on going from ppy to npy.

FIG. 4 shows a broad featureless red emission was observed for(corpy)Ir(ppz)₂ at room temperature in solution, with a biexponentialdecay of τ=1.64 μs (64%), 9.42 μs (36%). At 77 K, (corpy)Ir(ppz)₂produces a bright yellow emission shows distinct vibronic structure andthe lifetime becomes a first order decay (τ=9.42 μs). In PMMA,(corpy)Ir(ppz)₂ produced an orange emission that was found to haverelatively well defined band structure, again with a biexponential decay(τ=3.32 μs (14%), 8.17 μs (86%)). The quantum yield is increased by anorder of magnitude going from solution (Φ=0.02) to a rigid matrix(Φ=0.20) as the molecule becomes more constrained and less likely tonon-radiatively decay.

FIG. 5 shows a broad featureless orange-red emission was observed for(corpy)Pt(dpm) at room temperature in solution, with a monoexponentiallifetime of 5.05 μs. At 77 K, (corpy)Pt(dpm) produced a bright yellowemission shows distinct vibronic structure (λ_(max)=598 nm, τ=14.1 μs)and the lifetime is almost triple in magnitude. In PMMA, (corpy)Pt(dpm)produced an orange emission found to have more ordered vibronicstructure in between the spectra in solution and in 2-MeTHF glass(τ=12.2 μs). The quantum yield is increased by a factor of 4 going fromsolution (Φ=0.05) to a rigid matrix (Φ=0.20).

Although (corpy)Ir(ppz)₂ is slightly red-shifted from (corpy)Pt(dpm),the quantum yields of both platinum and iridium complexes are similar inboth solution (5.3 vs 2.2) and PMMA (20 vs 20), which is not normallyseen in heavy metal complexes with different metals and similar ligandsets. Non-radiative decay due to photoisomerization was ruled out as anexplanation after the compound was irradiated by 252 nm light inacetonitrile and was found to show no change after 8 hrs. Thus, theproperty appears to be due to high non-radiative rates of the complexesthat are both dictated by corannulene bowl inversion, leading to higherk_(nr) resulting in low quantum yield in solution. However, theirlifetimes differ in that (corpy)lr(ppz)₂ is second order, while theplatinum complex has a first order decay, which suggests two differentemission states for (corpy)Ir(ppz)₂.

Crystals of (corpy)Pt(dpm) and (corpy)Ir(ppz)₂ were grown by slowdiffusion of hexanes into dichloromethane of the metal complex. X raydiffraction analysis was carried out for both complexes. The unit cellof (corpy)Ir(ppz)₂ contains two (2) molecules of the complex, as wellas, two dichloromethane molecules in a triclinic P1 space group. Thestructure is shown in FIG. 6. The iridium center has pseudo-octahedralgeometry and the C^N ligands are found to coordinate in the merorientation. Two diastereomers are observed within the crystalstructure, i.e. Λ-P and the Δ-M where Λ and Δ describe the metal centerand P and M describe the corannulene bowl chirality. The Ir—N(corpy)bond (2.1218(16) Å) is longer than the Ir—N(ppz) bonds (2.0147(16) and2.0156(16) Å), but is comparable to other Ir—N(pyridyl) bonds inmer-complexes with phenyl pyridine ligands. Conversely, the Ir—C(corpy)bond (2.1033(18) Å) is longer than both Ir—C(ppz) bonds (2.0827(19) and2.0184(19)) and other mer-complexes with phenyl pyridine, which average2.087 Å. The C(corpy)—Ir—C(ppz) bond angle (170.86(7)°) and theN(ppz)—Ir—N(ppz) bond angle (174.19(6)°) are comparable to other mer-C^Ncomplexes.²

The structure of (corpy)Pt(dpm) is shown in FIG. 7. The unit cell of(corpy)Pt(dpm) contains 8 molecules in a monoclinic C 2/c space group.The corannulene bowl has a chirality of P as designated by thestereodescriptor system for chiral buckybowls based on fullerenenomenclature. The Pt complex has two chelating ligands in apseudo-square planar geometry around the metal center, with deviationsfrom ideal geometry most likely due to crystal packing forces. There areno metal-metal interactions, as the closest Pt—Pt distance is 5.65 Å.The bond lengths for Pt—C(1) (1.988(6) Å), Pt—N(1) (1.995(5) Å), Pt—O(1)(2.088(5) Å), and Pt—O(2) (2.021(4) Å) are slightly larger than thevalues reported for [(ppy)Pt(dpm)], and comparable with otherPt(β-ketonato derivatives). The bond angles for C(I)-Pt—N(1) (81.3(2)°)and O(1)-Pt—O(2) (89.98(18)°) were also found to be comparable withother cyclometalates of Pt. The bowl depth of corannulene was calculatedto be 0.895 Å which is slightly deeper than the bowl depth ofunsubstituted corannulene (0.87 Å).

Variable temperature NMR was carried out on (corpy)Ir(ppz)₂ to determinethe rate of inversion for the cyclometalated corannulene. The spectra ata range of temperatures, between room temperature and −70° C., are shownin FIG. 8. A combination of 2:1 deuterated dichloromethane:acetone wasused for (corpy)Ir(ppz)₂, so that good separation of all proton peakscould be achieved while also maintaining solubility of the complex atlower temperatures. The (corpy)Ir(ppz)₂ sample exhibited a loss incoalescence not only at the most downfield corrannulene resonances asthe sample is cooled, but also at other proton resonances on thepyrazole ring. As shown in FIG. 8, VT NMR was performed between roomtemperature (˜22° C.) and −70° C. As temperature decreases, the two mostdownfield resonances of corannulene broaden and then disappear into thebaseline. The individual corannulene resonances are difficult to assignin the cold spectra due to extensive overlap. Kinetic analysis of the VTspectra was carried out using the pyrazole resonance at 6.3 ppm. Thisproton has an anisotropic chemical shift depending on the position ofcorannulene bowl. Corannulene has an intrinsic dipole where electrondensity is localized in the base of the corannulene bowl. Depending onwhether the corannulene bowl is concave or convex to the pyrazole protonwill dictate whether the proton is shielded due to the corannulenedipole or deshielded when the bowl is inverted. This fluxional behavioris seen as an average chemical shift at room temperature.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

We claim:
 1. A compound having the structureM(L_(A))_(x)(L_(B))_(y)(L_(C))_(z): wherein the ligand L_(A) is

wherein the ligand L_(B) is

wherein the ligand L_(C) is

wherein x is 1 or 2; wherein y is 0, 1, or 2; wherein z is 0, 1, or 2;wherein x+y+z is 3; wherein ring A is a 5- or 6-membered heteroarylring; wherein X₁ is C or N; wherein the compound is heteroleptic, andthe dashed lines represent bonds to a metal M selected from the groupconsisting of Ir, Rh, Re, Ru, and Os; wherein R₇ and R₉ areindependently selected from group consisting of hydrogen, alkyl,cycloalkyl, aryl, and heteroaryl; wherein each R_(A), R₈, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ is independently selected from groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, carboxylic acid,ester, nitrile, and isonitrile; wherein rings C and D are eachindependently a 5- or 6-membered carbocyclic or heterocyclic ring;wherein R_(A), R_(C) and R_(D) each independently represent mono, di,tri, or tetra substitution, or no substitution; wherein each of R_(C)and R_(D) are independently selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, carboxylic acid, ester, nitrile, andisonitrile; or optionally, any two adjacent R_(A) can join to form afused ring with ring A, any two adjacent R_(C) can join to form a fusedring with ring C, any two adjacent R_(D) can join to form a fused ringwith ring D, or any two adjacent R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, andR₁₇ can join to form a ring with the corannulene ring system.
 2. Thecompound of claim 1, wherein at least one of R₇, R₈, and R₉ has at leasttwo C atoms.
 3. The compound of claim 1, wherein y is 1 or
 2. 4. Thecompound of claim 1, wherein each R_(A) is independently selected fromthe group consisting of hydrogen, alkyl, aryl, and combinations thereof.5. The compound of claim 1, wherein at least one R_(A) is selected fromthe group consisting of methyl, ethyl, propyl, 1-methylethyl, butyl,1-methylpropyl, 2-methylpropyl, pentyl, 1-methylbutyl, 2-methylbutyl,3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,2,2-dimethylpropyl, cyclobutyl, cyclopentyl, cyclohexyl, and partiallyor fully deuterated variants of each thereof.
 6. The compound of claim1, wherein the metal M is Ir.
 7. The compound of claim 1, wherein ligandL_(A) is selected from the group consisting of:

wherein R₁, R₂, R₃, R₄, R₅, and R₆ are independently selected from thegroup consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, carboxylic acid,ester, nitrile, and isonitrile; and wherein any two adjacent R₁, R₂, R₃,R₄, R₅, and R₆ are optionally joined to form a fused ring.
 8. Thecompound of claim 7, wherein at least one of R₁, R₂, R₃, R₄, R₅, and R₆is selected from the group consisting of ethyl, methyl, propyl,1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl, pentyl,1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl,1,2-dimethylpropyl, 2,2-dimethylpropyl, cyclobutyl, cyclopentyl,cyclohexyl, and partially or fully deuterated variants of each thereof.9. A compound comprising a ligand L_(A) according to formula (II):

wherein ring A is a 5- or 6-membered heteroaryl ring; wherein X₁, X₂, X₃and X₄ are each independently C or N; wherein R_(A) represents mono, di,or tri substitution or unsubstituted; wherein if any one of X₂, X₃ andX₄ are C then R_(A) is R₂, R₃ and R₄, respectively, and is independentlyselected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycioalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,carboxylic acid, ester, nitrile, and isonitrile; wherein any twoadjacent R₂, R₃ and R₄ are optionally joined to form a fused ring;wherein R₁₀, R₁₁, R₁₂, R₁₃ R₁₄, R₁₅, R₁₆, and R₁₇ are independentlyselected from the group consisting of hydrogen, deuterium, halide, alkylcycloalkyl heteroalkyl arylalkyl alkoxy, amino, silyl alkenyl,cycloalkenyl heteroalkenyl alkynyl aryl heteroaryl, carboxylic acid,ester, nitrile, and isonitrile; or any two adjacent R₁₀, R₁₁, R₁₂, R₁₃R₁₄, R₁₅, R₁₆, and R₁₇ can join to form a fused ring with thecorannulene ring system; and wherein the dashed lines represent bonds toa metal M selected from the group consisting of Ir, Rh, Re, Ru, and Os.10. The compound of claim 1, wherein the ligand L_(A) has a structureaccording to formula (III):

wherein X₂, X₃, X₄, and X₅ are each independently C or N; wherein if anyone of X₂, X₃, X₄, and X₅ are C then R_(A) is R₂, R₃, R₄, and R₅,respectively, wherein R₂, R₃, R₄, and R₅ are independently selected fromthe group consisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, carboxylic acid,ester, nitrile, and isonitrile.
 11. A device comprising an organic lightemitting device comprising: an anode; a cathode; and an organic layer,disposed between the anode and the cathode, comprising a compound havingthe structure M(L_(A))_(x)(L_(B))_(y)(L_(C))_(z): wherein the ligandL_(A) is

wherein the ligand L_(B) is

wherein the ligand L_(C) is

wherein x is 1 or 2; wherein y is 0, 1, or 2; wherein z is 0, 1, or 2;wherein x+y+z is 3; wherein ring A is a 5- or 6-membered heteroarylring; wherein X₁ is C or N; wherein rings C and D are each independentlya 5- or 6-membered carbocyclic or heterocyclic ring; wherein R_(A),R_(C), and R_(D) are each independently mono-, bi-, tri-,tetra-substituted, or unsubstituted; wherein R₇ and R₉ are independentlyselected from group consisting of hydrogen, alkyl, cycloalkyl, aryl, andheteroaryl; wherein R_(A), R₈, R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, andR₁₇ are independently selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, carboxyclic acid, ester, nitrile, and isonitrile; orany two adjacent R_(A) can join to form a fused ring with ring A, anytwo adjacent R_(D) can join to form a fused ring with ring D, or any twoadjacent R₁₀, R₁₁, R₁₂, R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ can join to form afused ring with the corannulene ring system; wherein each of R_(C) andR_(D) are independently selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, carboxylic acid, ester, nitrile, and isonitrile; orany two adjacent R_(A) can join to form a fused ring with ring A, anytwo adjacent R_(C) can join to form a fused ring with ring C, whereinthe compound is heteroleptic; and the dashed lines represent bonds to ametal M selected from the group consisting of Ir, Rh, Ru, and Os. 12.The device of claim 11, wherein the first device is a consumer productselected from the group consisting of a flat panel display, a computermonitor, a medical monitor, a television, a billboard, a light forinterior or exterior illumination and/or signaling, a heads up display,a fully transparent display, a flexible display, a laser printer, atelephone, a cell phone, a personal digital assistant (PDAs), a laptopcomputer, a digital camera, a camcorder, a viewfinder, a micro-display,a 3-D display, a vehicle, a wall, theater or stadium screen, and a sign.13. The device of claim 11, wherein the organic layer is an emissivelayer and the compound is an emissive dopant.
 14. The device of claim11, wherein the organic layer is an emissive layer and the compound is anon-emissive dopant.
 15. The device of claim 11, wherein the organiclayer further comprises a host material selected from a triphenylenecontaining benzo-fused thiophene or benzo-fused furan; wherein anysubstituent in the host material is an unfused substituent independentlyselected from the group consisting of C_(n)H_(2n+1), OC_(n)H_(2n+1),OAr₁, N(C_(n)H_(2n+1),)₂, N(Ar₁)(Ar₂), CH═CH—C_(n)H_(2n+1),C═C═C_(n)H_(2n+1), Ar₁, Ar₁-Ar₂ and C_(n)H_(2n+1) Ar₁; wherein n is from1 to 10; and wherein Ar₁ and Ar₂ are independently selected from thegroup consisting of benzene, biphenyl, naphthalene, triphenylene,carbazole, and heteroaromatic analogs thereof.
 16. The device of claim11, wherein the organic layer further comprises a host material thatcomprises at least one chemical group selected from the group consistingof triphenylene, carbazole, dibenzothiophene, dibenzofuran,dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene,aza-dibenzofuran, and aza-dibenzoselenophene.
 17. The device of claim16, wherein the host material is selected from the group consisting of:

and combinations thereof.
 18. A formulation comprising a compound ofclaim
 1. 19. An organic light emitting device comprising an organicemitting layer, disposed between an anode and a cathode, the organicemitting layer comprising a compound of claim
 1. 20. The compound ofclaim 1, wherein (i) ligand L_(B) is selected from the group consistingof:

(ii) ligand L_(C) is selected from the group consisting of:

 or (iii) options (i) and (ii).
 21. The compound of claim 9, wherein thecompound is homoleptic.
 22. The compound of claim 9, wherein thecompound is heteroleptic.
 23. A device comprising an organic lightemitting device comprising: an anode; a cathode; and an organic layer,disposed between the anode and the cathode, comprising a compound havingthe structure Pt(L_(A))(L_(B)): wherein the ligand L_(A) is

wherein the ligand L_(B) is

wherein ring A is a 5- or 6-membered heteroaryl ring; wherein X₁ is C orN; wherein rings C is a phenyl ring and D is a pyridine ring; whereinR_(A), R_(C), and R_(D) are each independently mono-, bi-, tri-,tetra-substituted, or unsubstituted; wherein R_(A), R₈, R₁₀, R₁₁, R₁₂,R₁₃, R₁₄, R₁₅, R₁₆, and R₁₇ are independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, carboxyclicacid, ester, nitrile, and isonitrile; or any two adjacent R_(A) can jointo form a fused ring with ring A, any two adjacent R_(D) can join toform a fused ring with ring D, or any two adjacent R₁₀, R₁₁, R₁₂, R₁₃,R₁₄, R₁₅, R₁₆, and R₁₇ can join to form a fused ring with thecorannulene ring system; wherein each of R_(C) and R_(D) areindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, carboxylic acid, ester, nitrile, and isonitrile; or any twoadjacent R_(A) can join to form a fused ring with ring A, any twoadjacent R_(C) can join to form a fused ring with ring C, wherein thecompound is heteroleptic; wherein L_(A) and L_(B) are optionally joinedto form a tetradentate ligand; and the dashed lines represent bonds tothe metal Pt.